Forced air roof-cleaning skewback channel and frame



Jan. 7, 1969 J. H. REIGHART 3,420,213

FORCED AIR ROOF-CLEANING SKEWBACK CHANNEL AND FRAME Filed Sept. 13, 1967Sheet of 2 Fig. 7

INVENTOR. a Y June HRGLYIMZIZZ 2'- E2 w N ATTORNEYS Jan. 7, 1969 J. H.REIGHART FORCED AIR ROOF-CLEANING SKEWBACK CHANNEL AND FRAME Sheet 2 ofFiled Sept. 13, 1967 1NVE.NTOR. JwneIiRez/g BY n mm United States Patent12 Claims ABSTRACT OF THE DISCLOSURE A forced air roof-cleaning skewbackchannel for an open hearth furnace having elongated horizontal slotstherein located just above the adjacent edge of the roof. A closedcorrugation in the web of the skewback channel, just above these slots,serves as a passageway for compressed air or other cleaning media, withdownwardly disposed jets to direct a blast of air toward the slots. Ifno strengthening corrugation is provided in the web of the skewbackchannel, a welded-on channel member or pipe may be substituted thereforfor providing positive motivation of the dust and dirt through theslots.

BACKGROUND OF THE INVENTION Field 0 the invention The invention relatesgenerally to skewback channels for supporting arched furnace roofs ofthe type disclosed in my prior Patents Nos. 2,919,683, dated Jan. 5,1960; 2,956,552, dated Oct. 18, 1960 and 3,173,403, dated Mar. 16, 1965,and more particularly to a forced air roofcleaning skewback channel.

In conventional open hearth furnace constructions, the roof arch issupported at opposite sides upon skewback channels mounted upon theusual buck-stays, and the frames of the charging doors of the furnaceextend upward in close proximity to the outer sides of the skewbackchannels.

Fly ash, dust and dirt descend upon the top of the arched furnace roofand slide by gravity down each side of the roof and accumulate thereonagainst the furnace sides of the skewback channels. With the basic brickfurnace roofs which have recently come into general use, the arch of theroof is higher to provide a larger combustion space for introducingoxygen into the furnace and running at higher temperatures.

This construction produces more of a trap between the top of the furnacearch and the skewback channels, whereby the accumulation of fly ash,dust and dirt on the roof becomes an acute problem as it not only has adetrimental effect on the furnace operation, but there is nosatisfactory way to remove the accumulation.

The need for the invention is primarily based on the fact that themajority of open hearth furnaces are utilizing chrome magnesite or otherbasic refractory brick in their roof structures. Such basic refractorybrick provides for longer roof life, with less maintenance, andwithstands higher operating temperatures demanded where oxygen lancesare used.

Such basic brick must be kept relatively free of dust and dirt whileoperating. If dust and dirt is allowed to accumulate thereon it acts asan insulating blanket or layer on the relatively cold upper face of thebrick causing the roof to deteriorate or burn out prematurely.

3,420,213 Patented Jan. 7, 1969 Description of the prior art Attemptshave been made to periodically blow the dust and dirt from such basicbrick roofs, as disclosed in McLain Patent No. 3,032,327, issued May 1,1962 and Roudabush Patent No. 3,162,152, issued Dec. 22, 1964. Suchcleaning apparatus momentarily removed the dust and dirt from the roofbut caused increased compacted and heavy accumulations thereof to settledown in the valleys adjacent to the skewback channels, thus weakeningsupport for the roof within that critical area between the top edges ofthe roof and the skewback channels.

SUMMARY OF THE INVENTION The invention may be briefly described ingeneral terms as comprising an open hearth furnace construction in whichskewback channels and charging door frames are independently supportedupon the usual buck-stays of the furnace. The skewback channels are soconstructed and positioned that the skew surfaces terminate at orslightly below the top of the arched roof at each side of the furnace.

In a preferred embodiment of the invention, a dust ledge is formed onthe skewback channel at the upper edge of the skew surface, as acontinuation of the upper surface of the brick roof.

Horizontally disposed slots are formed in the web of the skewbackchannel, the lower edges of said slots being located at or slightlybelow this dust ledge, or the top of the adjacent edge of the roof wherethe dust ledge is omitted.

A horizontally disposed passageway for compressed air is located justabove these horizontal slots and provided with downwardly and outwardlydisposed jets arranged to direct a blast of air toward the slots. Thus,fly ash, dust and dirt dropping upon the arched roof may slide downopposite sides of the roof by gravity and be discharged across the dustshelf and through said slots.

Each charging door frame is of a modified construction in order touncover the slots in the web of the skewback channel. For this purpose,the top of the upper water chamber, above the arch of the door frame, iscut off at or slightly below the lower edges of the slots in the web ofthe skewback channel.

At each side of the door frame, an upwardly disposed extension isprovided, vertically aligned with, and of substantially the same crosssection as the usual depending legs of the frame. These extensionsprovide means for locating the vertical inlet and outlet pipes for thewatercooling system of the frame.

An angle bracket is attached to the upper ends of these extensions onthe frame, reinforcing the top of the frame and providing means forattaching the usual lugs and other hardware to the frame. The ends ofthis angle bracket are attached to adjacent buck-stays.

The water-cooled nose of the door frame is located beneath the skewbackchannel protecting the same from impact when charging the furnace, andproviding further heat protection for the skewback channel.

The primary object of the present invention is to provide an open hearthor similar furnace construction in which the skewback channels andcharging door frames are so constructed and arranged that the archedfurnace roof will be substantially self-cleaning.

Another object of the invention is to provide a skewback channel havinghorizontal slots at the top surfaces 3 of the adjacent edge of the roofand means for directing aniair blast toward said slots.

A further object of the invention is to provide such a skewback channelin which the air passage is formed by closing a strengtheningcorrugation in the web thereof.

A still further object of the invention is to provide a skewback channelof the character referred to in which the air passage is formed bywelding a channel member to the web thereof above the slots.

It is also an object of the invention to provide a skewback channel ofthis type in which the air passage comprises a pipe welded to the webthereof.

A further object of the invention is to modify the construction of eachof the charging door frames by cutting off the top of the upper waterchamber of the frame, so that it terminates slightly below the loweredges of the slots in the web of the skew-back channel.

A still further object of the invention is to provide such a modifiedcharging door frame having upwardly disposed extensions at each sideedge of the frame, comparable in cross section and vertical alignmentwith the usual water-cooled legs of the frame, providing means forextending the door guide rails upward, and also for attaching an anglebracket extending across the full width of the frame for reinforcing thetop of the frame and for attaching the usual lugs and other hardwarethereto.

Another object of the invention is to provide for locating thewater-cooled nose of the charging door frame beneath the skewbackchannel for protecting the skewback channel from impact and for givingadded heat protection thereto.

Other objects of the invention are to provide various othermodifications of skewback channel associated with the modifiedconstruction of charging door frames for providing a substantiallyself-cleaning furnace roof.

The above and other objects, apparent from the drawings and followingdescription, may be attained, the above described difiiculties overcomeand the advantages and results obtained, by the apparatus, construction,arrangements and combinations, subcombinations and parts which comprisethe present invention, a preferred embodiment of which, illustrative ofthe best mode in which applicant has contemplated applying theprinciple, being set forth in detail in the following description andillustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary perspectiveview, looking from the outer or floor side, of a portion of an archedfurnace roof supported at one side by a skewback channel constructed inaccordance with the invention, and showing a charging door frameconstructed in accordance with the invention, the usual buck-stays andthe angle bracket for the top of the door frame being removed forpurpose of illustration;

FIG. 2 is a fragmentary perspective view, looking from the inner orfurnace side, showing a portion of an arched furnace roof supported atone side by a portion of a skewback channel embodying the invention,showing a portion of a charging door frame embodying the invention, theusual buck-stays and the angle bracket at the top of the door framebeing removed in this view also for purpose of illustration;

FIG. 3 is a front elevation of a charging door frame and a skewbackchannel embodying the invention, supported upon the usual buck-stays;

FIG. 4 is a top plan view of the parts shown in FIG. 3; FIG. 5 is avertical transverse section, taken on the line 55, FIG. 3;

FIG. 6 is a transverse sectional view through a preferred form ofskewback channel, in which the air passage is formed by closing thestrengthening corrugation in the web;

FIG. 7 is a similar view of a slightly modified form of skewbackchannel;

FIG. 8 is a similar view of a further modification;

FIG. 9 is a transverse sectional view through a modification of theskewback channel in which the air passage is formed by welding an anglemember to the web thereof;

FIG. 10 is a similar view of another modification of the skewbackchannel in which a pipe is welded to the web thereof; and

FIG. 11 is a transverse sectional view of a further modification of theskewback channel in which a pipe is welded to the web thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT Reference is now made to theembodiment of the invention illustrated in FIGS. 1-6, in which similarreference characters refer like parts throughout. The usual buckstays,which ordinarily support open-hearth furnace structures, are indicatedat 1 in FIGS. 3, 4 and 5. These buckstays are omitted from FIGS. 1 and2, for the purpose of better illustrating the novel skewback channel andcharging door frame to which the invention pertains, since thebuck-stays form no part of the invention and merely support the skewbackchannels and charging doors.

The skewback channel, which is preferably of the water-cooled type asillustrated, is indicated generally at 2. As in usual practice, skewbackchannels are attached to the buck-stays on opposite sides of the furnaceto support the arched brick roof indicated generally at 3. The roof maybe formed of basic refractory bricks such as chrome magnesite. Theskewback channels may be attached to the buck-stays in any usual andwell known manner.

Each skewback channel is provided with upper and lower water chambers 4and 5 respectively, as shown in FIGS. 5 and 6, for cooling the skewsurface 6, which terminates in a substantially horizontal, or preferablyslightly downwardly inclined dust ledge 7, located at or slightly belowthe adjacent portion 8 of the top of the furnace roof.

The usual web 9 extends upward from the back or outer side of eachskewback channel, terminating at its upper end in the inturned flange10. Cooling water may be continuously circulated through the upper andlower chambers 4 and 5 respectively, of each skewback channel, by theusual inlet and outlet pipes 11, as indicated in FIGS. 1, 3 and 4.

A series of horizontal slots 12 are formed in the web 9 of the skewbackchannel, the lower edges of these slots being flush with the top of thedust ledge 7, and preferably with their lower edges taper-cut in adownwardly and outwardly inclined surface corresponding with the slopeof the adjacent roof 3. As clearly shown in FIGS. 1, 2

and 3, each slot is of a length at least twice the distance betweenslots.

A charging door frame is indicated generally at 13 and comprises anupper water chamber '14 with depending water-cooled legs 15 forming thearched door opening 16 arranged to be normally closed by a water-cooledcharging door of any usual construction slidable within the door guides17 as in usual practice.

For the purpose of uncovering the slots 12 in the skewback channel, thetop of the water chamber 14 of the door frame terminates at or slightlybelow the lower edges of the slots 12, in a downwardly and outwardlyinclined surface, as indicated at 18.

Upwardly disposed extensions 19 are formed at each side edge of the doorframe, these extensions being in vertical alignment with and ofsubstantially the cross section of the legs 15 of the door. Theseextensions 19 provide means for extending the door guide rails 17 up andprovide means for locating vertical inlet and outlet water pipes 20 and21 respectively.

The extensions 19 also provide means for attaching an angle bracket,indicated generally at 22, which extends across the full width of thedoor frame and is connected to the upper ends of the extensions 19, thusreinforcing the top of the door frame and providing means for attachinglugs 23 or other usual hardware to the frame.

The water-cooled nose 24 of the door frame extends beneath the skewbackchannel 2 to protect the same from impact during charging of the furnaceand also giving added heat protection to the skewback channel.

The door frame may be attached to the buck-stays as by the attachingbrackets 25, which are connected to opposite ends of the angle bracket22 and to the buckstays respectively, as by the bolts 26 and 27.

The extension 19 at the outlet side of the frame provides a water-cooledchamber which may extend over the same to the top thereof. On the inletside the extension 19 is bulk-headed, as indicated at 28, on a levelwith the top 18 of the upper water chamber 14 of the door frame to forma water feed manifold and avoid the trapping of still water in thatisolated section.

With this construction, it will be obvious that fly ash, dust and dirtdropping upon the arched roof 3 of the furnace will by gravity slidedown the roof onto the dust ledge 7 of the skewback channel. The greateramount of fly ash and other dirt may slide by gravity across the sameand through the slots 12 in the web of the skew-back channel.

The principal feature of the invention is the provision of means forblowing any remaining accumulation of fly ash, dust and the like throughthe slots 12. For this purpose a passageway for compressed air, or othercleaning media, is located horizontally above the slots 12 and providedwith jets disposed downwardly and outwardly to direct an air blasttoward the slots.

Where the skewback channel is of the type having a reinforcingcorrugation 30 in the web as shown in FIGS. 1-6, this corrugation may beutilized as the passageway by welding a metal sheet or plate 31 acrossthe open rear side thereof. A plurality of jets 32 are formed in theunderside of the corrugation 30, being disposed toward the slots 12 asbest shown in FIG. 6, in order to direct a blast of air toward theslots. One end of the passageway thus formed may be closed as indicatedat 30 in FIG. 1 and a source of compressed air may be connected to theother end thereof.

The modification shown in FIG. 7 differs from that above described onlyin that the dust ledge 7 is substantially horizontal instead of beingdownwardly and outwardly inclined.

In FIG. 8 is shown a further modification in which there is no dustledge. All other parts are indicated by the same reference numerals asin FIGS. 6 and 7.

In FIG. 9 is shown another modification in which the air passage isformed by an angle member 33 welded upon the web 9 to form an airpassage. A plurality of jets 34 are formed in the underside of the airpassage thus provided and disposed toward the slots 12 in order todirect an air blast therethroug h.

In FIG. is shown another slight modification of skewback channel inwhich a pipe 35, with jets 36 therein, is welded upon the web 9 justabove the slots 12.

In the modification of FIG. 11 there is no dust ledge and a pipe 35,with jets 36 therein, is welded to the web 9 directly above the slots12.

A self-cleaning roof construction is thus provided which preventsaccumulation of fly ash, dust and dirt in the pockets formed by the websof the skewback channel at opposite sides of the furnace roof andordinarily interfering with the uniform operation of the furnace.

From the above it will he obvious that the novel form of skewbackchannel and charging door frame provides means for easily and readilycleaning the furnace roof and preventing accumulation of fly ash, dustor other dirt in the pockets formed by opposite sides of roof and theadjacent skewback channels.

It will also be seen that the dust and dirt removal through the slots 12is positively aided by means of the auxiliary air passages such as theclosed-in corrugations 30 (FIGS. 6, 7 and 8), or angles 33 Welded to web9 (FIG. 9) or pipe 35 (FIGS. 10 and 11). These various forms of cleaningmedia passageways carry pressurized air or other media which isdischarged from the openings or jets in the underside thereof in a blastdirected toward the slots 12.

Thus positive motivation is given to dust and dirt in its passage overthe dust shelf (if used) and through the slots, insuring a positivecleaning action of this critical area and minimizing the possibility ofany accumulation between the ends of the roof arch and the water-cooledskewback channels.

In the foregoing description, certain terms have been used for brevity,clearness and understanding, but no unnecessary limitations are to beimplied therefrom beyond the requirements of the prior art, because suchwords are used for descriptive purposes herein and are intended to bebroadly construed.

Moreover, the embodiments of the improved construction illustrated anddescribed herein are by Way of example, and the scope of the presentinvention is not limited to the exact details of construction.

Having now described the invention or discovery, the construction, theoperation, and use of preferred embodiments thereof, and theadvantageous new and useful results obtained thereby; the new and usefulconstructions, and reasonable mechanical equivalents thereof obvious tothose skilled in the art, are set forth in the appended claims.

I claim:

1. In a furnace of the open-hearth type having an arched roof, skewbackchannels at opposite ends of the arched roof, each skewback channelhaving a skew surface supporting the adjacent end of the arched roof andterminating at its upper end at substantially the adjacent portion ofthe top of the arched roof, and an upwardly extending web upon saidskewback channel, the improvement comprising a plurality of horizontalslots in said web, the lower edges of said slots being substantiallyflush with the adjacent top edge of the roof, a horizontal passagewayupon said web above the slots, there being jets in the underside of thepassageway directed toward said slots, and means for passing apressurized media such as compressed air through said passageway.

2. The improvement as defined in claim 1 in which there is a dust shelfon the skewback channel between the adjacent top edge of the roof andthe lower edges of said slots.

3. The improvement as defined in claim 2 in which the dust shelf issubstantially horizontal.

4. The improvement as defined in claim 2 in which the dust shelf isoutwardly and downwardly inclined.

5. The improvement as defined in claim 1 in which the passagewaycomprises a closed-in corrugation in the web.

6. The improvement as defined in claim 1 in which the passagewaycomprises an angle member welded to the we 7. The improvement as definedin claim 1 in which the passageway comprises a pipe welded to the web.

8. The improvement as defined in claim 1 in which a charging door frameis located at the outer side of one of the skewback channels, saidcharging door frame including an upper water chamber and depending legs,the top of said upper water chamber terminating slightly helow the loweredges of said slots.

9. The improvement as defined in claim 8 in which the top of the upperwater chamber is inclined outwardly and downwardly.

10. The improvement as defined in claim 8 in which there are upwardlydisposed extensions at the side edges of the door frame, said extensionsbeing vertically aligned with the depending legs, and a channel bracketconnected to the upper ends of said extensions.

7 8 11. The improvement as defined in claim 1 in which References Citedthe lower edges of the slots are taper-cut in a downwardly UNITED STATESPATENTS and outwardly inclined surface corresponding with the 2 919 6831/1960 Reighart 122 6 s1Pe of the adlacem 310321327 5/1962 McLain III263 44 12. The improvement as defined in claim 10 in which 5 there is aWater inlet into the top of one extension, the CHARLES MYHRE, PrlmaryExaminerlower end of said one extension being closed except for a U sC1, X R water outlet to the upper water chamber. 122 499; 263 44

